page_title: Evolution of cetaceans
hierarchical_section_title: Evolution of cetaceans
caption_attribution_description: English: A diagram showing the evolutionary history of cetaceans.
context_page_description: The Cetaceans are mammalian marine descendants of land mammals. Their terrestrial origins are indicated by:
  Their need to breathe air from the surface;
  The bones of their fins, which resemble the limbs of land mammals
  The vertical movement of their spines, characteristic more of a running mammal than of the horizontal movement of fish.
  The question of how land animals evolved into ocean-going leviathans was a mystery until recent discoveries in Pakistan revealed several stages in the transition of cetaceans from land to sea.
context_section_description: The Cetaceans (whales, dolphins and porpoises) are mammalian marine descendants of land mammals. Their terrestrial origins are indicated by:
  Their need to breathe air from the surface;
  The bones of their fins, which resemble the limbs of land mammals
  The vertical movement of their spines, characteristic more of a running mammal than of the horizontal movement of fish.
  The question of how land animals evolved into ocean-going leviathans was a mystery until recent discoveries in Pakistan revealed several stages in the transition of cetaceans from land to sea.
caption: A phylogeny showing the relationships among cetacean families.[1]
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